Exercise-induced ischemia in mildly symptomatic patients with coronary artery disease identifies a subgroup with a high likelihood of left main disease, 3-vessel disease, and sudden death during subsequent therapy. Many such patients have no chest pain during exercise despite objective evidence of ischemia. To determine the prognostic implications of "silent" ischemia with exercise, we studied 131 consecutive patients with mild or no symptoms and with preserved resting left ventricular function by exercise ECG and radionuclide angiography. Patients developing angina with exercise had a greater prevalence and severity of reversible myocardial ischemia. However, those patients manifesting an ischemic response to stress had similar prevalence of left main or 3-vessel disease and a similar mortality rate during medical therapy whether or not chest pain developed with exercise. Thus, the prognosis in patients with "silent" vs symptomatic ischemia during exercise testing is similar.